Re: Meaning of FFP in packet-drop

FPP is :

A fast filtering processor (FFP) is incorporated into the EPICs and GPICs, in order to accelerate packet forwarding and enhance packet flow. The FFP is essentially a state machine driven programmable rules engine. Filters are applied to packets received by the FFP, through the use of masks so that certain fields of a packet may be evaluated. The filters utilized by FFP are defined by a rules table, where that table is completely programmable by the CPU, through the CMIC. The actions taken based on the filtering of the FFP include 802.1p tag insertion, 802.1p priority mapping, IP TOS (type-of-service) tag insertion, sending of the packet to the CPU, discarding or dropping of the packet and forwarding the packet to an egress port.

The FFP counters do not necessarily mean that its dropping the data packet in their network, it is something the switch CPU decides and cannot be user manipulated. It enables switch applications to set filters on some of the important fields from Layer 2 to layer 7 of the packet. The filters are used mainly for packet classification based on certain protocol fields in the packets. Based on packet classification various actions can be taken. Two classes of actions are defined: In-Profile Actions and Out-Profile Actions. When a packet is in in-profile, the actions associated with the in-profile are taken. When the packet is out of profile, the actions associated with out-profile actions are taken. Some of the actions may involve discarding the packets, sending the packet to the CPU, sending the packet to Mirrored-to Port, sending the packet on certain COS priority queue, changing the type Of Service (TOS Precedence), remarking DSCP etc.

Please check the below link which provides a detailed explanation of FFP mechanism, specifically check for (Fast Filter Processing) on the document: